Department of Medical Physics and Radiospectroscopy, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland.
Department of Inorganics and Analytical Chemistry, Poznań University of Medical Sciences, Grunwaldzka 6, 60-780, Poznan, Poland.
AAPS PharmSciTech. 2022 Mar 21;23(4):93. doi: 10.1208/s12249-022-02234-8.
The H nuclear magnetic resonance (NMR) relaxometry method was applied to investigate the physical stability of an active pharmaceutical ingredient (API) and, for the first time, its recrystallization process in an amorphous solid dispersion system (ASD). The ASD of felodipine and polyvinylpyrrolidone (PVP) was prepared using the solvent evaporation method in a mass ratio of 50:50. In the first stage of the study (250 days), the sample was stored at 0% relative humidity (RH). The recovery of magnetization was described by one-exponential function. In the second stage (300 days in 75% relative humidity), the recrystallization process of felodipine was studied, showing in the sample three components of equilibrium magnetization related to (i) crystalline felodipine, (ii) water, and (iii) felodipine and PVP remaining in the ASD. The study shows that the H NMR relaxometry method is a very useful tool for analysing the composition of a three-phase system mixed at the molecular level and for the investigation of recrystallization process of API in amorphous solid dispersion system.
H 核磁共振（NMR）弛豫测量法被应用于研究一种活性药物成分（API）的物理稳定性，这也是首次将其应用于无定形固体分散体系统（ASD）中的重结晶过程。使用溶剂蒸发法，以 50:50 的质量比制备了硝苯地平与聚乙烯吡咯烷酮（PVP）的 ASD。在研究的第一阶段（250 天），样品在 0%相对湿度（RH）下储存。磁化的恢复由单指数函数描述。在第二阶段（300 天，75%RH），研究了硝苯地平的重结晶过程，结果表明在样品中有三个与（i）结晶硝苯地平、（ii）水和（iii）ASD 中剩余的硝苯地平和 PVP 相关的平衡磁化分量。研究表明，H 核磁共振弛豫测量法是一种非常有用的工具，可用于分析在分子水平上混合的三相系统的组成，并用于研究 API 在无定形固体分散体系统中的重结晶过程。
